Investigations on brown rot of apricots caused by Sclerotinia fructicola (Wint.) Rehm. II. The relationship of the potassium status of apricot trees to brown rot susceptibility

Abstract

It is shown that under Tasmanian conditions there is a negative relation between the potassium status of apricot trees and their susceptibility to brown rot. From regression equations calculated, it is suggested that trees with a potassium content of about 4.6 per cent. in oven-dry leaves would be resistant to brown rot. Difficulty was experienced in increasing the potassium content of the trees by soil or spray applications of potassium fertilizer, but when this was achieved, some reduction in brown rot incidence occurred. Regular annual soil dressings of potassium chloride at the rate of 2 lb per tree was the most satisfactory treatment tested.